She probably won't even notice if you don't respond to that statement at all and doesn't register what you say anyway. It's automatic for some people, like, "How are you?" If you feel compelled, just say, "OK." and go on the the next conversation. Don't fret about it.

Ugh, I hate this. I get it. I have the same impulse when people come over, and I haven't had time to scrub every corner. But come on. It's clean enough. No one will notice that baseboard in the corner. No one will realize that you vacuumed two days ago and not today. I know someone who used to do this, back when I was kind of a slob, and it made me feel almost guilty. Like, if this is what you consider a mess, what would you think of my house? I will never invite you over, not even after a good cleaning.

So even though I want to sometimes, I make myself not say stuff like that when people come over. No one notices or cares, and it just makes your guest feel awkward. When people say it to me, I say something like, "Wow, I wonder what you'd think of my house." I really don't see mess when I go to other people's house, unless it gets in to real grossness territory (filthy kitchen counters, visibly grimy toilet). I simply don't care. So I try to make myself assume that of them.